This invention relates to the pilot nozzle of the gas turbine combustor intended to improve flame stabilization. The invention further relates to the pilot nozzle of the gas turbine combustor that improves flame stabilization by using the circulation of the combustion gas arising from combustion in the gas turbine combustor.
FIG. 8 shows a cross section of a pilot nozzle 83 of a conventional gas turbine combustor. The pilot nozzle 83 is a dual type that injects two types of fuels, namely, fuel oil 81 and fuel gas 82. The fuel oil 81 flows along the longitudinal axis (xe2x80x9coil-flow channelxe2x80x9d) of the pilot nozzle 83 and is diffusion-injected from the tip of the pilot nozzle 83. On the other hand, the fuel gas 82 flows through a plurality of fuel-flow channels 84 and is diffusion-injected obliquely forward relative to the pilot nozzle 83. The fuel-flow channels 84 are laid longitudinally at, say, eight locations along the outer circumferential periphery of the pilot nozzle 83. Peripherally to the pilot nozzle 83 flows in spirals the pilot air that has passed through the pilot swirler 85, the swirling air then in a mixture with the fuel gas producing a spurt of pilot flame.
The conventional pilot nozzle 83 has a drawback that the fuel consumption is rather high, and there is a demand for curbing the fuel consumption. The combustion of fuel oil from the main nozzle constitutes the main combustion in the combustion chamber, because of which the curbing of the use of fuel oil injected from the main nozzle is in no sense appropriate. On the other hand, the flame of fuel gas 82 injected from the pilot nozzle 83 is functionally meant to just aid in the ignition of fuel oil injected from the main nozzle. It is this very function of fuel gas 82 that renders it possible for fuel consumption to be curbed without impairing the role of the pilot nozzle 83, if and only if flame stabilization can be improved nonetheless.
It is an object of this invention to provide a pilot nozzle of the gas turbine combustor that utilizes circulation of the combustion gas arising from the combustion taking place in the combustor and improves flame stabilization.
The pilot nozzle of a gas turbine combustor according to one aspect of the present invention comprises a first structure, near a main nozzle of a combustor that injects fuel oil, having a flow channel for a fuel gas and an outlet for the fuel gas, the first structure diffusion-injecting the fuel gas obliquely forward through the outlet to maintain a flame and to aid ignition of the fuel oil injected from the main nozzle, and a second structure which circulates in whirls a combustion gas generated due to the combustion of the fuel gas.
The pilot nozzle of the gas turbine combustor according to another aspect of the present invention comprises a central axis, a flow channel for a fuel gas, the flow channel being parallel to the central axis, and an outlet for injecting the fuel gas and aiding ignition of the fuel oil injected from the main nozzle. A portion of the flow channel in the vicinity of the outlet is bent towards the central axis.
Other objects and features of this invention will become apparent from the following description with reference to the accompanying drawings.